Ran Ookubo assumes guardianship of the protagonist following the death of his grandfather, Saizo Igano, her childhood companion and unrequited first love. Their bond fractured by ninja traditions forbidding marriage outside the clan, her enduring rivalry with Suu Matsuno—another of Saizo’s former admirers—ignites a decades-long feud between their rival schools, Kin'gyoku and Ōgyoku.

As Kin'gyoku Academy’s headmistress, she governs with eccentric authority, masking shrewd intellect beneath a veneer of absent-mindedness that beguiles students. Her guardianship stems from a final letter Saizo penned before his supposed death, binding her to shepherd the protagonist’s transition from secluded mountain life to Tokyo’s bustling streets.

A strategist cloaked in compassion, she deduces Saizo faked his demise to catalyze his grandson’s growth, guarding this truth even when confronting him in disguise during a school trip to Iga. Silent admiration from the Vice-Principal and subtle manipulations of academy politics underscore her layered influence, positioning her as both mentor and enigmatic pillar within the institution.

Her decisions weave ancestral codes with modern strife, the schools’ conflict mirroring her unresolved history with Saizo and Matsuno. Though advanced in years, she orchestrates fragile alliances and mentors the next generation, serving as a living conduit between the protagonist’s inherited ninja legacy and the complexities of his urban future.